Comparative application of biological and ninhydrin- derivatized spectrophotometric assays in the evaluation and validation of amikacin sulfate injection

Abstract Instrumental techniques are preferred over bioassay methods for antibiotic quantification mainly due to speed and ability to quantify metabolites in biological samples; however, the potency and biological activity of these drugs cannot be assessed. Two methods - agar well diffusion (bio-assay) and spectrophotometric methods were used to evaluate amikacin sulfate injection. Agar plates were inoculated with S. aureus inoculum; zones of inhibition from its susceptibility to amikacin were obtained, while spectrophotometric absorption at 650 nm of ninhydrin- derivatized amikacin in phosphate buffer (pH 8) was measured. Methods performance showed linearity from 1 - 16 µgmL-1 (bioassay, r = 0.9994) and 10-50 µgmL-1 (spectrophotometric, r = 0.9998). Molar absorptivity was 2.595 x 104 Lmol-1cm-1. Limits of detection and quantification were 1.07 and 3.24 µgmL-1 respectively for bioassay method, while corresponding values for spectrophotometric method were 0.98 and 2.97 µg mL-1. Relative standard deviations were ≤ 2.0% for both methods, with recoveries from 95.93 - 100.25%. Amikacin in brands ranged from 97.53 ± 2.68 to 100.84 ± 1.82%, student's t-test was ≤ 2.78 (n = 4) with respect to label claim for both methods. Experimental paired t-test (t = 2.07; n = 4) and F-test (F = 3.94; n = 4) values indicated no significant difference between both methods, hence comparable and can jointly be used in quality control assessment of antibiotics

Development and validation of UV spectroscopic methods for simultaneous estimation of ciprofloxacin and tinidazole in tablet formulation.

Two simple, accurate, precise, reproducible and economical UV spectroscopic methods (A & B) for simultaneous estimation of Ciprofloxacin and Tinidazole in tablet dosage form have been developed. Method A employs solving of simultaneous equations based on the measurement of absorbance at two wavelengths, 271nm and 318nm which are the λmax values of Ciprofloxacin and Tinidazole respectively in phosphate buffer (pH 6.8). Method B is based on the principle of Q-Analysis where in the absorbance was measured at 292nm (iso-absorptive point) and 271nm (λmax of Ciprofloxacin)in phosphate buffer (pH 6.8). Ciprofloxacin and Tinidazole shows linearity at all the selected wave-lengths and obeys Beer’s law in the concentration range of 10-35μg/mL and 10-80μg/mL respectively. Recovery studies for Ciprofloxacin and Tinidazole were performed and the percentage recovery for both the drugs was obtained in the range of 98.1-99.7% (Method A) and 98.0-100.4% (Method B) confirming the accuracy of the proposed method. Both the methods showed good reproducibility and recovery with %RSD less than 2. Statistical validation of the data shows that the proposed methods can be successfully applied for the routine analysis of drugs in commercial tablets.

Development and validation of UV spectroscopic methods for simultaneous estimation of ciprofloxacin and tinidazole in tablet formulation.

Two simple, accurate, precise, reproducible and economical UV spectroscopic methods (A & B) for simultaneous estimation of Ciprofloxacin and Tinidazole in tablet dosage form have been developed. Method A employs solving of simultaneous equations based on the measurement of absorbance at two wavelengths, 271nm and 318nm which are the λmax values of Ciprofloxacin and Tinidazole respectively in phosphate buffer (pH 6.8). Method B is based on the principle of Q-Analysis where in the absorbance was measured at 292nm (iso-absorptive point) and 271nm (λmax of Ciprofloxacin)in phosphate buffer (pH 6.8). Ciprofloxacin and Tinidazole shows linearity at all the selected wavelengths and obeys Beer’s law in the concentration range of 10-35μg/mL and 10-80μg/mL respectively. Recovery studies for Ciprofloxacin and Tinidazole were performed and the percentage recovery for both the drugs was obtained in the range of 98.1-99.7% (Method A) and 98.0-100.4% (Method B) confirming the accuracy of the proposed method. Both the methods showed good reproducibility and recovery with %RSD less than 2. Statistical validation of the data shows that the proposed methods can be successfully applied for the routine analysis of drugs in commercial tablets